1. Field of the Invention
The present invention relates to a toner for use in developing an electrostatic latent image. In addition, the present invention relates to a method for preparing the toner. Further, the present invention relates to an image forming method for forming a visual image using the toner.
2. Discussion of the Background
Recently, toner (hereinafter referred to as oil-less toner) in which a wax is dispersed to impart good releasability to the toner has been used for electrophotographic image forming apparatus using an oil-less fixing device which fix toner images without applying an oil to a fixing member.
On the other hand, in order to prepare a small-sized high speed image forming apparatus, it is necessary to miniaturize the toner feeding passage thereof, which feeds toner to the developing device of the image forming apparatus. Particularly, it is necessary for full color image forming apparatus to have four toner feeding passages and four developing devices. Therefore, such full color image forming apparatus typically have small-sized and complex toner feeding passages. In this case, color toners are pressed in the feeding passages, and thereby the color toners are agglomerated, resulting in deterioration of image qualities (such as formation of spot images (such as black spot images) in a solid image).
In addition, a one-sheet copying or printing operation is frequently performed in copiers having a printer function. Even in such a one-sheet copying or printing operation, the developer (toner) is agitated every copying or printing operation, resulting in increase of the time, during which pressure (stress) is applied to the toner. In this regard, problems in that the external additives of the toner is released therefrom, and/or embedded into the toner particles, resulting in agglomeration of the toner particles, thereby deteriorating the image qualities are caused.
A published unexamined Japanese patent application No. (hereinafter referred to as JP-A) 2006-201706 discloses a toner for developing an electrostatic latent image, which has an inter-particle force of from 1.0×10−9 to 1.0×10−6 N, a compression adhesiveness of from 20 to 100 gf and a compression bulk density of from 300 to 800 kg/m3, when the properties are measured by pressing the toner for 1 minute at 25° C. under a compression stress of 15 kg/cm2.
However, when this toner is an oil-less toner (i.e., a toner in which a wax is dispersed), the wax tends to exude from toner particles and the exuded wax is present on the surface thereof if the temperature of the toner feeding passage or the developing device significantly increases, resulting in agglomeration of the toner particles, thereby deteriorating image qualities.
Because of these reasons, the inventors recognized that there is a need for a toner which can produce high quality images without causing the above-mentioned problems.